Dry concentrator



July 18, 1933.

l. c. LIGHTFOOT 1,918,343-

DRY CONCENTRATOR Filed Sept. 28. 1931 2 Sheets-Sheet 2 Elwin-"loo v Patented July 18, 1933' V un ruosra ISAAC o. LIGH'rroor, or sen BERNARDINO, CALIFORNIA DRY coNonNrR-Arron Application filed September 28, 1931. Serial No. 565,434.

This invention relates to improvements in dry concentrators and has reference more particularly'to an improved apparatus and method for separating fine gold particles 5 from ground quartz, gravel or other nonmetallic material. a

It is well known that there exists in many parts of this country, and also in many other countries, great quantities of gravel and sand with which is mixed gold in the form of line powder or fialtes. These deposits areusually found in places where the rainfall is very limited and where wateris very searc/e and therefore the separation of the gold cannot be effected by any method that requires a considerable quantity of water.

It is one of the objects of this invention to produce an apparatus that shall be so constructed that by means of it gold can be scparated from any dry powdered material and.

this apparatusistherefore especially well adapted for desert places. where water is unavailable. v v It has been found from experience that if K dry ground ore or gravel is firstcarefully screened so as to remove all particles above a certain size and then deposited on an inclined chute that is vibrated by mechanical means in such a way as to cause a layer of this material to flow downwardly, and then pass a strong current of air upwardly through it, the constant agitation produced by the mechanical vibration of the chute and by t 1e current of air permits the gold particles to gravitate to thevbottom of the chute where they can be collected. v

This invention briefly described consists of an apparatus having a supporting framework comprising, in part, a box-like receptacle open at the top and having its top edges inclined towards one end, a chute is located above this receptacle and has its lower end pivotally connected with the lower end of the receptacle. The sides and upper end of the receptacle are connected with the correspond ing sides and end of-thechute by means of canvas that permits the chute to move'relative to the receptacle. Means is provided for vibrating the chute and for depositing sand 50 on its upper end. The bottom of'the chute is formed of pervious material. Extending transversely of the chute above the bottom are riflles over which the materialmust flow in its passage .7 downwardly; Means is-provided for blowing air into the receptacle and for increasing the air pressure to such L an extent that air currents will pass upwardly through the layer of ore. .Havingthus' briefly described the inven tion, the same will nowbe described in detail, and for this purpose reference will be had to the accompanying drawings in which one embodiment of the invention has been illus trated, and .in which: p Y i A Fig. 1 is a sideelevati'on' of anappara-tus constructed in accordance with this invention; v V I Fig. 2 is an end View of the apparatus look inglinthe direction of arrow 2,Fig. 1; Fig. 3 is a section take on line 3 3, Fig. .1; Fig. 4C is a top plan view of the chute; Fig. 5 is a section taken on linef :55, Fig.4. v Fig. 6 is a section taken on line 6+6, 4:; and o v 7o Fig. 7 is a section taken on line 7-7, Fig. 6; I V Y In the drawings reference numeral 1 represents a supporting surface on which the apparatus rests. The apparatus consists of a frame work comprising twovertical supports 2 that are located at the lower end of the ap paratus and two other vertical supportsB located at the opposite end. Thevertical supports 3 extend upwardly a considerable distance and cooperate with similar supports 4 in supporting a rotary screen 5. The sev .eral supports 3 and 4C are connected by horizontal members 6 so as toform a rectangular C framework. Sincethe specific construction of this framework is independentof theiinvention that is claimed herein, it will not be described with any greater particularity than is foundto be necessary for the purpose-of 9 properly explaining theinvention. The vertical supports 2, 3 and iars connecteclby neans of a hor'izontal steel mem ber Sand a similar steelmember Q extends upwardly in an inclined direction from mem= ber 2'.to support 3. Box-like container 10 is supported by tl' e framework comprising sup sides 1 and ends 18 and 14. The end mem- 7 her 18 is higher than end member 14 and the upper edges of the sides are inclined, all in the manner shown in Fig. 5. One end of the bottom is provided with an outlet pipe 15 through which material can be removed when the receptacle is cleaned. Supported above the open end of the receptacle, is achute that has been designated in its entirety by reference numeral 16. The chute consists of two parallel side members 17 that are connected at their ends by transverse members 18. A bottom 19 formed from eighty mesh screen extends between the side'me'mbers 17 along the center line of the latter in" the manner shown in Fig. 5. Extending transversely of the chute are 'riiiles 20 to'the under side of which the screen is attached. A transverse member 21 is locatedadjacent the upper end of the chute and the upper end of the screen bottom is attached to this transverse member. An inclined plate 22extends from member 21 to the upper end member 18' and this is spaced a short distance from the upper surface of member 2'1 so asto provide openings 23 for the escape of air. Member 21is also provided with openings 24. Each of the riiiies is provided with openings 25 I that extend from their lower surface to a point near the top, as shown in Fig. 5. A. removable board 26 1s provided between the lowermost riffie and thelower end 18, as shown in the drawings. Located between one of the ends of the rifiie and one side member 17 is-a removable board 27 that can be raised when desired and when this is raised, an opening like that indicated by reference numeral 28 in Fig. 8 is provided. l Vhen the chute is to becleaned, the contents can be swept to the side having the opening 28 and can then be swept down wardly to the opening provided by the removal of board 26. Located beneath the screen 19 is another screen 29 that is preferably made of ninety mesh wire and located a short distance belov. this is a strip of canvas 30 that is supported on a screen 31 of large stops 34. means of a screw 85 as seen most clearly in mesh. A. few riflles 32 are secured transversely of screen 29.

The sides of the screen are provided with brackets 33or some equivalent means and these are adapted to come in contact with These stops are adjustable by Fig1 6. The stops limit the downward movement of the chute and by adjusting the stops the amount of vibration can be controlled.

For the'purpos'e of vibrating the chute, cams- 36 have been provided. These cams. are secured to shaft 37, one end of which is pro contact-s.

cooperates. Directly above each of the cams is a bracket 40 whose under surface has a hardened steel plate 41 with'which the cam The cam can be constructed in the manner shown in Fig. 7, or in some other equivalent wayt box 42 surrounds the cam and contains oil sothat the cam surfaces are always properly lubricated. The'bracket has downwardly projecting sides 43 that'ove'rlap the sides of the box 42 so as to exclude dust and dirt. Although the cam has a definite throw, the actual extent of the vibration can be controlled by the stops 34 as above intimated.

Located at the rearo'f the receptacle is a blower 44 that is connected with the interior of the'receptacle by means of a pipe 45. Secured to the inner sides of the receptacle are two or more deflector plates 46 that serve to direct the air upwardly against the bottom of the chute. Plates 46 are preferably'so connected with the receptacle that they canv be readily, removed when the latter is to be cleaned. The end 14 of the receptacle is pro 'videdwith a screened opening 47 that is protected by means of a baffle plate 48. This opening permits some of the alr to escape and this also provides a current of air fromthe pipe throughout the entire length of the; receptacle.v In addition to thefan 44, an

other fan which has been indicated by refer ence numeral 49,v has been provided. The outlet from this fan has been designated by reference numeral 50 and has at its upper end a, wide nozzle 51 that terminates within the upper end of the chute directly beneath the plate 22, as shown in Fig. 5. A pipe-52 eX- tends from this nozzle to the chute 53 that comes from the rotary screen. Whenblower 49 is in operation, it produces a strong blast of air that is directed downwardly into the space between the screens 19'and 29 and this air serves to produce a strong air current through the ore as it flows downwardly over the screen.

, The power is delivered to the shaft 54 by means of-a belt'that cooperates with a pulley 55. The fan 44 is driven from this shaft by means of a belt 56-and fan 49 is also driven from this shaft by means of a beltv 57. Lo-

cated above the fans is a shaft 58 that is driven by means of a belt 59'and this shaft has i a pulley 60 with which a belt 61 cooperates.

Belt 61 transmits power to a pulley 62 that rotates the screens in a manner quite appar-' ent from the drawings. The end of shaft 54 has a bevelled gear 63 that cooperates with a corresponding bevel gear 64 on the end of shaft65. sprocket, wheel '66 that cooperates with a sprocket chain67 which in turn cooperates with a sprocket wheel 68 on the'end ofshaft 69. A universal joint 70 connects the end of shaft 69 with shaft 71, and this shaft eX- The other end of shaft 65 has a tends'upwardly parallel to the upper edge of one of the sides of the chute, and is journalled in bearings 72. Shaft 71 is provided FlfilBS and when shaft 71 is rotated, the rods 75 and fingers wur reciprocate, thereby keeping the material on the upper. side of the ritiies agitated so as to facilitate the settling of the gold particles and the passage of the air through the fan at this point. The sand that overflows the rifiles will be subjected to a blast of air coming through the openings 25 and the action of this air will serve to remove dust and light particles. There is, of course, a continuous flow of air upwardly through the screen bottom and this in conjunction with the vibration of the chute and the clownward motion of the fan keeps the particles in constant motion, thereby permitting the gold particles to gravitate towards the bottom. The small particles of gold will pass through the screen 19 and becaught on the riiiles 32 on the lower screen. If any gold particles pass through screen 29, they will be caught on the canvas; The gold that is present in the sand which this machine is clesigned to operate on, is ,so line that some will even pass through the canvas and this will settle on the bottom of the receptacle. The diagonal plates 46 act as battles-to direct the air upwardly in the manneralready pointed out. i

With a machine constructed in the manner described, the sand is deposited inlthe hopper 78 and from this it passes into the n)- tary screens 5 where it is subjected to a sue cession of screenings and the finer particles pass downwardly through the chute 53 and are deposited on the upper surface of boards 22. The fans are operated in the manner de-' scribed and, simultaneously therewith the chute is vibrated. The sand is distributed quite uniformly over the board 22 and thence passes downwardly along the chute overflowing the rliiies, and finally passlng out over thelower end 18. Duringthe downward passage, the. constant agltation of the sand together with the cleaning action of the air currents, permits.

the gold to gravitate downwardly, the

' larger particles being retained on the screen for the length of time desired, it is stoppedand the board 27 removed together with the The material on screen 19 is then swept into the opening 28'and from thence board 26.

Fingers/T7 extend downwardly.

downwardly into the receptacle. 1 The chute can be removed if desired forfthe purpose of cleaning the receptacle, althoughthis can be V quite satisfactorily effected through the"7 opening normallycclosed by board' 26. The material removed from the receptacle is passed to a cleanup barrel where'it is amalgamated with mercury after which it is separated from themercury in theusual manner.

best when the material is absolutely dry, and it is therefore especiallywell adaptedifor arid countries where there is goldmixed withthe can be operated by meansof an internal coirbustion engine and as this requires merely The machine as described above operates without the use of water and in fact operates 'sand, but no water available; -The-machine the driestplaceswhich has" heretofore been impractical'because practically all machines and methods that havehcretoi ore been in i snipped or transported without difficulty on trucks, or even on pack mules and is therefore available for any location. a a t The machine described above and claimed herein is adapted for use with all kiuds'of powdered oreas well as with dry sand and gravel. The term ore or sand. is intended to embrace all kinds of dry powdered ma-e terial containing metal particles, such as ground quartz ore, rotten quartz, sand and gravel and it is not limited to any particular material. v I 1 Having described the invention what is claimedas new is: i y 1. An apparatus for separating gold from dry powdered ore, or the like, comprising,

in combination, a" support formed input 1 by a box-like receptacle having its upper end open and inclined downwardly towards one end, a chute located above the receptacle and inclined in the same direction as the open end of the receptacle, the lower end of the chute being connected to the lower end ofthe receptacle by hinges, the sides and the other end of the receptacle being connected to the sides and corresponding end of the chute by means of flexible fabric, the bottom of the chute being formed of pervious material,

there being a pervious partition located beheath thebottom and spaced from the latter, 'a plurality of riffles extending transversely ofthe chute on the upper surface of the bottom,means for depositing a layer ofmaterial on the upperend of the chute, means for im- 7 parting to the chute an up and down-vibration whereby the material will be agitated chute, means for blowing air into the receptacle whereby: the air pressure therein will be increased above atmospherlc and a flow of chanical 'means for stirring the material above the rililes. v

2. An. apparatus for separating gold from dry powdered ore, or the like, comprising, in combination, a. support formed in part by, a

box-like receptacle having its upper end open, a chute located above the receptacle and inclined in the direction of its length, the lower end of the chute being connected to one end ofthe receptacle, the sides and theother end of the-receptacle being con nected to the sides and corresponding end of the chute by meanso't flexible fabric, the bottom of the chute being formed of pervious material there being a p ervious partition located beneath the bottom and spaced from the latter, a pluralityof riiiles extending transversely of the chute onthe'upper surface of the bottom means for depositing a layer of material on the upper end. of the chute, means for imparting to the chute an up and downvibration whereby the material will be agitated and made to move clown- Wardly along the chute, means for blowing air into the receptacle whereby the air pressure therein'will be increased above atmospheric, whereby a flow of air is produced through the pervious bottom of the chute and through the material, mechanical meansfor stirrin the material above the miller; and

a separate blower for directing a stream of air into the space between the bottom and the partition. i

3. An apparatus for-separating gold from dry sand, or the like, comprising, in combination, a support formed in part by, a born like receptacle having its upper end open, a chute located above the receptacle and inclined in the direction of its length, the lower end of the chute being connected to one end of the receptacle, the sides and-the other end of the receptacle being connected to the sides and corresponding end of the chute by means of flexible material, thebotto-m 01" the chute being formed of pervious material, there being a pervious partition located beneath the tween the bottom and the bottom and. spaced from the latter,.a plurality of .riflles extending transversely of the chute on the upper surface of the bottom, means for depositinga layer of material on the upper end of the chute, means for imparting to the chute an up and down vibration-whereby the material will be agitated f and made to move downwardly along the chute, means for blowing air into the receptacle whereby the air pressuretherein will be increased above atmospheric, a flow of air produced through the perviousbottom oi":- the chute and through the material, the rifiies having openings extending from the bottoms the lower end o1 the chute beingconnected to one end of the receptacle, the sides and the other end of the receptacle being connected to the sides'and corresponding end of the chute by means of flexible fabric, the bottom of the chute being formed of pervious material there being a pervious partition loeated beneath the bottom and spaced from the latter, a plurality of riiiies extending transversely of the chute on the upper surface of the bottom, means fordepositing. a layer of material on the upper end of the chute, means for imparting to the chute an up and down vibration whereby the material. will be agitated and made to move down-' Wardly along the chute, means for: blowing air into the receptacle whereby the air pressure therein will be increasedabove atmospheric, a flow of air produced through the pervious bottom of the chute and through the material, the riffles having openings eX- tending from the bottoms to a point on the lower side a short distance below. the top, mechanical means for stirring the material above the ritlles, and a separate blower for directing a blast of air into the space hepartition.

ISAAC o. niei-irroor,

its 

